This invention relates to bacterial cellulose (BC) of which ribbon-shaped microfibrils are artificially modified to improve Young's modulus and a method of producing the same.
The bacterial cellulose can be used as various industrial materials, clothing materials, materials for medical supplies, functional materials, materials for foods and so on.
It is known that Acetobacter xylinum ATCC 23769 produces a mat-shaped cellulose which can be used for medical pads (Japanese Patent KOKAI 59-120159). It is also known that Acetobacter aceti subsp. xylinum ATCC 10821, etc. produce bacterial cellulose composed of ribbon-shaped microfibrils (U.S. Pat. No. 4,742,164). The size of the ribbon-shaped microfibrils is said to be 20 to 50 nm (Ed. by Tokyo Techno. Forum Secretariat, “Jinrui to Bio (Humanity and Bio)”, P329, 1993 Yomiuri Nippon Television (enter) which may be measured without discrimination of the major axis (width and the minor axis (thickness).
The bacterial cellulose is produced as floc or suspended matter in a form of sheet, dispersion, grain or the like by static culture or aeration agitation culture which effects entangling of fibers. However, although the above macroscopic variation occurs, ribbon-shaped microfibril and properties of the bacterial cellulose are substantially not varied.
Structure and properties of bacterial cellulose are slightly different according to the type of bacterium. However it has not been reported to produce modified bacterial cellulose by changing the form of cellulose-producing bacteria artificially to vary ribbon-shaped microfibrils.